Microscopes of the kind cited above have been known for some time in the existing art. Very generally, in upright and inverted light microscopes, focusing of the specimen is accomplished by way of a corresponding positioning of the specimen relative to the objective, specifically in such a way that a specimen region to be detected is arranged in the focal plane of the objective. This can be achieved on the one hand by the fact that the objective, optionally together with the objective turret receiving the objective, is positioned along the optical axis relative to the specimen. In this case the specimen, for example mounted on a conventional specimen slide, is clamped in a corresponding holder on the microscope stage, this microscope stage then not being moved in the direction of the optical axis of the microscope objective. This type of focusing is usually utilized with inverted light microscopes. On the other hand, the microscope stage can be arranged movably relative to the microscope stand, and positioned in the direction of the optical axis for focusing. In this case the objective does not perform a motion in the direction of its optical axis relative to the microscope stand. The latter type of focusing is usually utilized with upright light microscopes. Focusing with the aid of the microscope stage also exists, for purposes of the present invention, when the microscope stage comprises a mechanism with which a specimen slide performs a positioning relative to the objective with the aid of a linear or pivoting motion controlled by a galvanometer, as is the case, for example, with the assignee's confocal laser scanning microscopes.
In both cases, a focusing of the specimen to be investigated is usually performed by the fact that an operator operates an operating element arranged on the microscope stand, as a result of which either the objective or the microscope stage is positioned, as a function of the operator's operation, relative to the microscope stand in the direction of the optical axis of the objective. The operating element is a rotary knob, but usually two rotary knobs (one rotary knob for fine drive and one rotary knob for coarse drive) which are arranged rotatably about a rotation axis and are directly or indirectly coupled to a shaft. Rotation of the rotary knob by the operator causes rotation of the shaft coupled to the operating element. The rotation of the shaft is in turn transferred, usually in mechanical fashion, into a linear motion of the microscope stage or the objective in the direction of the optical axis.
The operating element is usually arranged laterally at a certain height on one side wall of the microscope stand, usually a few centimeters away from a support surface on which the microscope stands. This arrangement of the operating element is optimized for an average operator's hand size, but it is arranged too low for operators with large hands, and too high for operators with small hands. For users with a hand size deviating from the average hand size, microscope operation is therefore fatiguing over the long term and as a result, not ergonomic in that respect.